Safety fuse igniter and crimping tool



July 17, 1956 R. v. WAKEFIELD 2,754,754

SAFETY FUSE IGNITER AND CRIMPING TOOL Filed Aug. 14, 1952 IN V EN TOR.

RALPH V. WAKEFIELD 1 4-44 2 AGENT point wax, rubber, or the like.

SAFETY. FUSE IGNITER AND c Ralph V. Wakefield, East Alton, Ill., assignor to Olin Mathieson Chemical Corporation, a corporation of Virginia Application August 14, 1952, Serial No. 304,385

4 Claims. (Cl. 102-23) This invention relates to a fuse igniter and more specifically to a device for attaching the case of an ignition cartridge to a safety fuse cord and for setting off the ignition cartridge to activate the fuse.

Charges of blasting explosive are frequently set off with safety fuse which consists generally of a core of inflammable medium such as a black powder composition forming a powder train of predetermined burning rate enclosed in a sheath of some fibrous or cellular material such as paper or some textile provided in turn with a covering of impervious material such as metal foil or with a waterproof coating such as asphalt, high melting In preparation for blasting operations, to one end of safety fuse cut to suitable length there is attached a detonator which is then inserted into a cavity formed in the main charge of the blasting explosive. Subsequently the other end of the fuse, split lengthwise to expose more of the core material black powder, is ignited with a burning punk or with a match or even with an electric igniter. According to U. S. Patent Nos. 58,639 (Hagenmeyer) and 997,800 (Fuller) and British Patent No. 1,267 of 1873 it has been proposed to ignite the fuse by means of a percussion cap or cartridge; but because of the disadvantages of the ignition means heretofore available this method of fuse ignition has never been accepted.

An object of the invention is to provide a new and improved device with which ignition of safety fuse may be accomplished by means of a.- blank cartridge containing a suitable ignition mix and having an open end for admission of one end of a cord of safety fuse.

Another object is to provide a device so constructed as to be adapted to ignite the fuse conveniently and safely Without untimely and forceful separation of the device, the cartridge and the fuse from each other.

Another object is to provide a simple manually operable device for facilitating blasting operations in the mining, quarrying and construction industries.

Still further objects and advantages will be obvious from the description which follows when read in connection with the accompanying drawing in which:

Fig. l is a plan view of one embodiment of the device of this invention.

Fig. 2 is an elevational view partly in cross section of the device of Figure 1, taken on the line IIII.

Fig. 3 is a cross sectional view of one type of cartridge suitable for use in connection with the device of this invention.

Fig. 4 is a cross sectional elevational view taken on line IV-IV showing a safety fuse and the igniting cartridge of Figure 3 positioned in the device of this invention.

In accordance with this invention there is provided a fuse ignition device utilizing a blank cartridge and comprising a jaw structure which constitutes a breech block adapted not only for chambering the cartridge but also for crimping and holding the cartridge case and means for discharging the cartridge while chambered in the aws.

The preferred embodiment of this invention is in the form of a plier-like implement since a pair of pliers is a familiar tool, one of the least difficult to manipulate manually, and one preferred by blasting operators. All the elements of the device are designed around and include a pair of crossed levers 1 and 2 pivotly connected intermediate the ends of the levers by the rivet or pivot bolt 7. The pair of ends 3 and 4 on one side of the pivot serve as handles for manually bringing the other pair of ends 5 and 6, known as the jaws, into and out of articulation. ln'the edge adapted to be brought into articulation with the other jaw, each jaw 5 and 6 is provided with a semi-circular groove 8, forming a chamber for receiving and frictionally holding either a rim-fire or centerfire cartridge while the jaws are held in contact.

At one end of each semi-circular groove 8 there is a circumferential shelf or offset portion 9 for reception of the rim 19 at the base of an igniting cartridge. Adjacent the other end of each of the semi-circular grooves forming the halves of the cartridge chamber there is provided on the interior wall of each groove one or more circumferentially extending and interiorly directed protrusions or semi-circular lands 11 each forming in efiect a contraction in the firing chamber formed by grooves 8 in the blocks or jaws 5 and 6. On closure of these jaws, the lands 11 function to crimp and seize the cartridge preparatory to firing it, thus fixing the cartridge on the fuse and preventing ejection of the cartridge or parts of it on firing.

To accomplish ignition of the cartridge, one of the levers carries a strip of resilient metal such as the steel leaf spring or strip 12 one end of which is fastened to the handle 4 by any suitable means such as fastening stud 13 to support the spring while the other end carries a firing pin 14 positioned in proximity to the end of the chamber formed by the grooves 8 when the jaws are closed. Proper alignment of the firing pin with the chamber in the jaws is assured by seating the fastened end of spring 12 in an elongated depression 22 formed in handle 4 and extending in the direction of the groove 8 in the jaw 5. The trigger mechanism may be safely retracted when not in use by turning strip 12 about stud 13 until the firing pin 14 falls into the recess 21 in handle 4.

A suitable ignition cartridge for use with the device of this invention, Figures 3 and 4, consists of a tubular metal case 15 open at one end for reception of the fuse 16, having an enlarged rim 10 at the base and a percussion sensitive primer 19 containing a suitable prirnin minture which develops considerable heat with a minimum of pressure on firing. Such mixture may be disposed in a rim-fire type as well as the centerfire type cartridge'shown. Where the cartridge is much larger in diameter than the safety fuse, the open or anterior portion 20 of the cartridge is necked down, e. g., to about 0.218 of an inch, as shown to barely pass the safety fuse about which the mouth or anterior portion is to be crimped. To accommodate the configuration of the ignition cartridge, the diameter of the grooves in the jaws of the igniting tools of this invention is proportioned similarly along the length thereof to match the cartridge. For example, where a rimless centerfire cartridge is contemplated, offset 9 takes the form of a thin inwardly projecting rim serving to initially position the cartridge.

in operating the device described herein, one end of the safety fuse 16 is inserted into the open end 20 of the cartridge 15, and the cartridge is laid in the grooves 8 of the open jaws. By squeezing the handles 3 and 4,

the jaws are brought together and the lands 11 in the grooves 8 firmly crimp the mouth or anterior portion of the ignition cartridge about the safety fuse 16, as shown in Figure 4, thus not only securing the cartridge to the fuse but also'positively holding cartridge against ejection from the firing chamber formed by the juxtaposed grooves of the closed jaws 5 and 6 at the moment when the priming mixture of the blank cartridge goes off. Firing of the cartridge is accomplished by merely lifting the firing pin end of spring 12, backing it off from the jaws a suitable amount, and then releasing the spring to allow the pin 14 to strike the base of the cartridge either at the rim or at the center depending upon whether the cartridge is a rim-fire or centerfire cartridge respectively.

To provide a device of maximum usefulness, various other utilitarian features may be incorporated without detracting from the invention. For example, handle 3 is provided with a pointed end forming a blasting carttridge'punch or piercer 17. Also the nose of jaws 5 and .6 are provided with cutting blades 18 to form a fuse cutter and slitter. Further the crimping lands 11 may be used to crimp a detonator to the other end of the safety fuse prior to insertion of this end into the depression punched into a cartridge of the main blasting charge.

, Although the foregoing specific embodiment has been described in considerable detail, it is to be understood that changes and modifications may be made therein without departing from the spirit and scope of this invention as set forth in the appended claims;

What is claimed and desired to be secured by Letters Patent of the United States is:

1. A device for igniting safety fuse with a primed blank cartridge containing a fuse kindling mix comprisingmeans for chambering the cartridge and for crimping the mouth of the cartridge substantially completely around an end of a fuse enveloped therein, said chambering and crimping means comprising a pair of members having jaws with complementary surfaces adapted to be brought into and out of contiguity by articulation of said members upon application of an operatingforce, a transverse groove in each of said surfaces of said jaws and adapted to form together with the other of said grooves a chamber for embracing at least the side walls of said cartridgeon closure of said jaws, circumferentially extending inwardly protruding means in each of said grooves for deforming the cartridge at its mouth substantially circumferentially against the fuse to hold said cartridge and fuse end together in substantially sealed relationship, and means mounted on at least one of said members for discharging the chambered and crimped cartridge whereby the powder train of said fuse is kindled substantially without emission of flash to the surrounding atmosphere.

2. A device for igniting safety fuse" by means of a primed blank cartridge comprising a pair of crossed levers pivotally connected intermediate the ends thereof, jaws formed on one pair of ends of said levers and having juxtaposed surfaces adapted to be articulated into and out of contact, a transverse groove of semi-circular cross section in each of the juxtaposed edges of said jaws and adapted to form together with the other of said grooves a chamber for frictionally engaging an ignition cartridge on closure of said jaws, a circumferentially extending and interiorly protruding projection on the walls of each groove adjacent one end thereof for crimping and holding said cartridge, and a strip of spring metal one end of which is attached to one of said levers in a depression aligning said spring strip in the direction of one end of the transverse groove in the jaw of said lever and the other end of which is free and carries a firing pin normally positioned over said end of said transverse groove whereby said chambered cartridge may be fired to ignite said fuse by manually lifting off and subsequently releasing said firing-pin-carrying end of said strip.

3. A device for igniting safety fuse by means of a primed blank cartridge comprising two members pivotally connected to allow the juxtaposed surfaces of said members to be articulated into and out of contact, a transverse groove of semi-circular cross section in each of the juxtaposed surfaces of said members and adapted to form together with the other of said grooves a chamber for embracing an ignition cartridge on closure of said members, means associated with each of said grooves for crimping and holding said cartridge, and trigger means for discharging the ignition cartridge, said trigger means consisting of a strip of spring metal one end of which is attached to one of said members in a depressionaligning saidtstrip in the direction of one end of the transverse groove in said member and the other end of which is free and carries a firing pin normally positioned over said end of said transverse groove whereby said chambered cartridge may be fired to ignite said fuse by manually lifting off and subsequently releasing said firing-pin-carrying end of said strip.

4. A device for igniting safety fuse comprising means for crimping substantially around one end of the fuse a cartridge containing in the base thereof a percussion sensitive fuse kindling mix while simultaneously chambering said cartridge and fuse end, and a leaf spring one end of which is free and carries a firing pin for discharging the cartridge whereby the burning mix kindles the powder train of said fuse.

References Cited in the file of this patent FOREIGN PATENTS 1,640 Great Britain Ian. 27, 1892 Of 1892 15,098 Great Britain Mar. 16, 1911 of 1910 

1. A DEVICE FOR IGNITING SAFETY FUSE WITH A PRIMED BLANK CARTRIDGE CONTAINING A FUSE KINDLING MIX COMPRISING MEANS FOR CHAMBERING THE CARTRIDGE AND FOR CRIMPING THE MOUTH OF THE CARTRIDGE SUBSTANTIALLY COMPLETELY AROUND AN END OF A FUSE ENVELOPE THEREIN, SAID CHAMBERING AND CRIMPING MEANS COMPRISING A PAIR OF MEMBERS HAVING JAWS WITH COMPLEMENTARY SURFACES ADAPTED TO BE BROUGHT INTO AND OUT OF CONTIGUITY BY ARTICULATION OF SAID MEMBERS UPON APPLICATION OF AN OPERATING FORCE, A TRANSVERSE GROOVE IN EACH OF SAID SURFACES OF SAID JAWS AND ADAPTED TO FORM TOGETHER WITH THE OTHER OF SAID GROOVES A CHAMBER FOR EMBRACING AT LEAST THE SIDE WALLS OF SAID CARTRIDGE ON CLOSURE OF SAID JAWS, CIRCUMFERENTIALLY EXTENDING INWARDLY PROTRUDING MEANS IN EACH OF SAID GROOVES FOR DEFORMING THE CARTRIDGE AT ITS MOUTH SUBSTANTIALLY CURCUMFERENTIALLY AGAINST THE FUSE TO HOLD SAID CARTRIDGE AND FUSE END TOGETHER IN SUBSTANTIALLY SEALED RELATIONSHIP, AND MEANS MOUNTED ON AT LEAST ONE OF SAID MEMBERS FOR DISCHARGING THE CHAMBERED AND CRIMPED CARTRIDGE WHEREBY THE POWDER TRAIN OF SAID FUSE IS KINDLED SUBSTANTIALLY WITHOUT EMISSION OF FLASH TO THE SURROUNDING ATMOSPHERE. 